Tilting buckets are well known in the construction industry and the like for allowing an operator of a machine to properly grade sloped surfaces by tilting the bucket at the desired angle. In many bucket designs, the maximum angle accommodated by the pivot design for the bucket is approximately 45 degrees.
The coupling system used to connect the bucket to a machine may include hook members that are spaced apart a predetermined distance in a direction that is perpendicular to the pivot axis of the bucket. In such a case, if the hooks are too far apart and it is desirable to provide a 45 degree angle of tilting, it is often necessary to cut clearance notches such as v-shaped notches in the spill guard or similarly positioned structure of the bucket assembly to allow the 45 degree angle of tilt to be accomplished. However, dirt and debris may evade through the notch during use, such as when the full 45 degrees of tilt is not needed because the coupling or adapter subassembly of the bucket assembly is not in the notch. This happens to be the case for most excavating and grading operations. As a result, this area may become clogged with dirt or debris, which may interfere with the operation of the bucket assembly. Also, parts of the hydraulic system such as the hoses may become abraded, necessitating maintenance or replacement.
Looking at FIGS. 1 thru 3, a prior art tilting bucket assembly 100 may be seen that is used with a quick coupling mechanism known in the art. Hook members 102 are provided that define a predetermined distance D102 between them. The spill guard 104 and its backup plate 114 include V-shaped clearance notches 106 that allow the tilting of the bucket assembly 100 to be performed while also allowing dirt and debris to infiltrate near the workings of the tilting mechanism 108 including the hydraulic hoses 110 and hydraulic cylinders 112. Furthermore as best seen in FIG. 2, the pivot height PH, which is the distance from the base plate 116 to the pivot axis 118, cannot be reduced significantly due to the structural interference between the bucket subassembly 120 and the adapter subassembly 122 including the base plate 116 and hook members 102. Also, interference between the base plate 116, torsion tube 124 and the hydraulic cylinders 112 and hoses 110 would also present a problem should the pivot height PH be reduced. As also shown in FIG. 2, this also makes reducing the tip radius TR, which is measured from the hook center 128 (may also be described as the center of the aperture of the hook member) to the front working edge 126 of the bucket difficult. This may make the force necessary to move the tilting bucket assembly 100 of FIGS. 1 thru 3 through a work material such as soil greater than desirable due to the increased leverage exerted by the work material near the tip or front working edge 126 of the bucket.
It should be noted that typically dimensions like the tip radius TR and pivot height PH are measured with the bucket subassembly 120 and adapter subassembly 122 are in their purely horizontal and vertical positions. More specifically, the tilt angle is zero degrees such that the front working edge 126 and base plate 116 are horizontally oriented.